Perishable items such as produce and meat are often transported in refrigerated trailers, railcars, or ocean-going containers that can in turn be transported on ships, trains or trucks. Such cargo transport devices are typically equipped with a refrigeration unit which conditions the air inside the cargo space, thereby maintaining desired temperatures and humidities during transportation or storage.
Refrigerated trailers, railcars and containers can be configured so as to enclose a single, large cargo space. Their refrigeration units will accordingly maintain the entire cargo space at the same temperature and humidity unless the cargo area is somehow divided. However, when the perishable cargo does not fill the entire trailer, cooling the entire cargo area is unnecessary and costly. It causes unnecessary strain and wear on the refrigeration unit, increases fuel consumption, raises transportation costs, and lengthens the time necessary to cool the perishable cargo after any temperature aberration.
Movable partitions and bulkheads having a specialized construction which permit the cargo space of trailers, rail cars, and containers to be readily divided into sections of varying sizes are available. These bulkheads and partitions have been used on a widespread basis for separating cargo to permit multi-temperature transport. The structure and configuration of partition and bulkhead systems differ somewhat depending on whether they are being deployed in a trailer, railcar, or container.
In many applications, the cargo area adjacent the access door is kept at controlled temperature. Oftentimes such a cargo area extends from a roll-up trailer door to a bulkhead or partition wall which in turns defines another cargo area which is controlled to be at a different temperature and/or humidity. If the access door is not substantially sealed, conditioned air and/or ambient air may pass through the portal, increasing fuel consumption and causing undue strain and wear on the climate control system. In many instances, the climate control system may not be able to maintain the cargo area at the desired temperature, which in turn causes damage to or destruction of temperature sensitive cargo such as food products.
The leakage of conditioned and/or ambient air may be particularly pronounced in trailers having roll-up doors that have a construction similar to household garage doors. Roll-up doors tend to move up and down during transport, causing the associated seals to move away from their intended positions and creating gaps around the periphery of the door. Moreover, the seams between the panels of the roll-up door can also permit significant exchange of conditioned and ambient air.
However, similar problems exist with virtually any type of portal providing ingress or egress from a conditioned cargo area. Swing-type doors often have inferior insulating properties and peripheral seals. The performance of bulkheads, partitions, and any associated access doors can also be improved by improved thermal insulation and/or peripheral sealing.